adjust parsing to raise nicer exceptions
snoyer
parent
fcb648b9bb
commit
21ca2fe6a8
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@ -43,8 +43,15 @@ except NameError:
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COMMANDS = set('MmZzLlHhVvCcSsQqTtAa')
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UPPERCASE = set('MZLHVCSQTA')
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COMMAND_RE = re.compile(r"([MmZzLlHhVvCcSsQqTtAa])")
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FLOAT_RE = re.compile(r"[-+]?[0-9]*\.?[0-9]+(?:[eE][-+]?[0-9]+)?")
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TOKEN_RE = re.compile(r"""
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(
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[MmZzLlHhVvCcSsQqTtAa] # command
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(?:[-+]?[0-9]*\.?[0-9]+(?:[eE][-+]?[0-9]+)?) # float
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)
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""", re.VERBOSE
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)
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SEPARATORS = ', \t\r\n'
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# Default Parameters ##########################################################
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@ -3179,19 +3186,28 @@ class Path(MutableSequence):
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next(b, None)
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return zip(a, b)
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def _tokenize_path(self, pathdef):
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for x in COMMAND_RE.split(pathdef):
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if x in COMMANDS:
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yield x
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for token in FLOAT_RE.findall(x):
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yield token
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@staticmethod
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def _tokenize_path(*pathdef_lines):
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# yield line number and offset in addition to token
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# so we can raise syntax errors
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for lineno, line in enumerate(pathdef_lines):
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start = 0
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for token in TOKEN_RE.split(line):
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if token.strip(SEPARATORS):
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yield token, lineno, start
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start += len(token)
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def _parse_path(self, pathdef, current_pos=0j, tree_element=None):
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# In the SVG specs, initial movetos are absolute, even if
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# specified as 'm'. This is the default behavior here as well.
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# But if you pass in a current_pos variable, the initial moveto
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# will be relative to that current_pos. This is useful.
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elements = list(self._tokenize_path(pathdef))
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# we need to keep the pathdef split by lines so we can retrieve a specific line
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# to throw syntax errors
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pathdef_lines = pathdef.splitlines()
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elements = list(self._tokenize_path(*pathdef_lines))
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# Reverse for easy use of .pop()
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elements.reverse()
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@ -3200,27 +3216,43 @@ class Path(MutableSequence):
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start_pos = None
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command = None
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while elements:
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def pop_float(elements):
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try:
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token, lineno, start = elements.pop()
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try:
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return float(token)
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except ValueError:
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line = pathdef_lines[lineno]
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end = start + len(token)
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raise self._syntax_error('invalid token %r' % token, lineno, line, start, end)
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except IndexError:
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lineno = len(pathdef_lines) - 1
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line = pathdef_lines[lineno]
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end = len(line) - 1
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raise self._syntax_error('not enough arguments', lineno, line, end, end)
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if elements[-1] in COMMANDS:
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while elements:
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if elements[-1][0] in COMMANDS:
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# New command.
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last_command = command # Used by S and T
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command = elements.pop()
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command = elements.pop()[0]
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absolute = command in UPPERCASE
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command = command.upper()
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else:
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# If this element starts with numbers, it is an implicit command
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# and we don't change the command. Check that it's allowed:
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if command is None:
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raise ValueError("Unallowed implicit command in %s, position %s" % (
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pathdef, len(pathdef.split()) - len(elements)))
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token, lineno, start = elements[-1]
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end = start + len(token)
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line = pathdef_lines[lineno]
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raise self._syntax_error("missing command", lineno, line, start, end)
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last_command = command # Used by S and T
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if command == 'M':
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# Moveto command.
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x = elements.pop()
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y = elements.pop()
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pos = float(x) + float(y) * 1j
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x = pop_float(elements)
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y = pop_float(elements)
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pos = x + y * 1j
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if absolute:
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current_pos = pos
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else:
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@ -3245,34 +3277,34 @@ class Path(MutableSequence):
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command = None
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elif command == 'L':
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x = elements.pop()
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y = elements.pop()
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pos = float(x) + float(y) * 1j
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x = pop_float(elements)
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y = pop_float(elements)
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pos = x + y * 1j
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if not absolute:
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pos += current_pos
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segments.append(Line(current_pos, pos))
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current_pos = pos
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elif command == 'H':
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x = elements.pop()
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pos = float(x) + current_pos.imag * 1j
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x = pop_float(elements)
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pos = x + current_pos.imag * 1j
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if not absolute:
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pos += current_pos.real
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segments.append(Line(current_pos, pos))
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current_pos = pos
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elif command == 'V':
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y = elements.pop()
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pos = current_pos.real + float(y) * 1j
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y = pop_float(elements)
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pos = current_pos.real + y * 1j
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if not absolute:
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pos += current_pos.imag * 1j
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segments.append(Line(current_pos, pos))
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current_pos = pos
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elif command == 'C':
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control1 = float(elements.pop()) + float(elements.pop()) * 1j
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control2 = float(elements.pop()) + float(elements.pop()) * 1j
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end = float(elements.pop()) + float(elements.pop()) * 1j
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control1 = pop_float(elements) + pop_float(elements) * 1j
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control2 = pop_float(elements) + pop_float(elements) * 1j
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end = pop_float(elements) + pop_float(elements) * 1j
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if not absolute:
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control1 += current_pos
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@ -3297,8 +3329,8 @@ class Path(MutableSequence):
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# to the current point.
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control1 = current_pos + current_pos - segments[-1].control2
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control2 = float(elements.pop()) + float(elements.pop()) * 1j
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end = float(elements.pop()) + float(elements.pop()) * 1j
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control2 = pop_float(elements) + pop_float(elements) * 1j
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end = pop_float(elements) + pop_float(elements) * 1j
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if not absolute:
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control2 += current_pos
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@ -3308,8 +3340,8 @@ class Path(MutableSequence):
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current_pos = end
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elif command == 'Q':
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control = float(elements.pop()) + float(elements.pop()) * 1j
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end = float(elements.pop()) + float(elements.pop()) * 1j
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control = pop_float(elements) + pop_float(elements) * 1j
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end = pop_float(elements) + pop_float(elements) * 1j
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if not absolute:
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control += current_pos
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@ -3333,7 +3365,7 @@ class Path(MutableSequence):
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# to the current point.
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control = current_pos + current_pos - segments[-1].control
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end = float(elements.pop()) + float(elements.pop()) * 1j
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end = pop_float(elements) + pop_float(elements) * 1j
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if not absolute:
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end += current_pos
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@ -3343,11 +3375,11 @@ class Path(MutableSequence):
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elif command == 'A':
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radius = float(elements.pop()) + float(elements.pop()) * 1j
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rotation = float(elements.pop())
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arc = float(elements.pop())
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sweep = float(elements.pop())
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end = float(elements.pop()) + float(elements.pop()) * 1j
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radius = pop_float(elements) + pop_float(elements) * 1j
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rotation = pop_float(elements)
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arc = pop_float(elements)
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sweep = pop_float(elements)
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end = pop_float(elements) + pop_float(elements) * 1j
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if not absolute:
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end += current_pos
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@ -3369,3 +3401,12 @@ class Path(MutableSequence):
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current_pos = end
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return segments
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@classmethod
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def _syntax_error(cls, msg, lineno, line, offset,end_offset):
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filename = '<svg-d-string>'
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try:
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return SyntaxError(msg, (filename, lineno+1, offset + 1, line, lineno, end_offset + 1))
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except IndexError:
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# on python < 3.10
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return SyntaxError(msg, (filename, lineno+1, offset + 1, line))
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@ -178,10 +178,20 @@ class TestParser(unittest.TestCase):
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path2 = Path(Line(-3.4e+38 + 3.4e+38j, -3.4e-38 + 3.4e-38j))
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self.assertEqual(path1, path2)
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def test_errors(self):
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self.assertRaises(ValueError, parse_path,
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'M 100 100 L 200 200 Z 100 200')
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def test_error_missing_command(self):
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with self.assertRaises(SyntaxError) as e:
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parse_path('M 100 100 L 200 200 Z 100 200')
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assert "missing command" in e.exception.msg
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def test_error_invalid_token(self):
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with self.assertRaises(SyntaxError) as e:
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parse_path("M 0 \n1 N 2 3")
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assert "invalid token" in e.exception.msg
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def test_error_not_enough_arguments(self):
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with self.assertRaises(SyntaxError) as e:
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Path("M 0 1\n 2")
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assert "not enough arguments" in e.exception.msg
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def test_transform(self):
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